Breathing apparatus



April 19, 1927.

G. s. MCCAA BREATHING APPARATUS Fi'led Aug. 12. 15322 4 Sheets-Sheet 1 April 19, 1927. 1,625,419

G. S. MGCAA BREATHING APPARATUS Filed Aug. 12-. 1922 4 Sheets Sheet 2 F IG-Ea 'WHHLUIHM INVE/ TOR Apyil 19, 1921 1,625,419

e. s. M cA BREATHINGAPPARATUS VV ITNEvSSES' a sigh c the plane of view Patented Apia 19,1927.

pram Erica.

GEQRGE S. MCCAA, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR T E SAFETY APPLIANCES COMPANY, OF PITTSBURGH,

PENNSYLVANIA.

EENNSYLVANIA, A CGBPQRA'EION QB Bana'rnrne arranarus.

Application filed August 12, 1922. Serial No. 581,374.

Theinvention relates to self-contained oxygen breathing apparatus that is to say, apparatu of the-character used bymlners, firemen and others when operating in atmospheres containing noxious or poisonous gases.

'l he general object of the invention 'is to provide a breathing apparatus which is of simple and practical construction, and which will operate efiiciently witlra minimum liability of any of its several units tailing toproperly function. A more specific obyect eral parts of the apparatus that it will be compact in form and convenient to operate.

Further objects will appear from the following description of the apparatus.

[he-invention is illustrated in the accompanying drawings, of which Fig. 1 is an elevation of a complete apparatus, the view bein taken on the side of the apparatus, whirih, when the apparatus is in Ioperatiomis adjacent to the user; Fig. 2 a vertical sectional view ot a portion of the apparatus, being indicated by the line lll-H, Fig. 1; Fig. 3 a vertical sectional view taken substantially at right angles to the plane of view of Fig. 2; Figs. l, 5 and 6 detail sectional views taken, respectively, on

the lines llV-IV, VQV and VI-" L '3; Fig. 7 a vertical central sectional view of the mouthpiece and valves for controllin the flow of air through the apparatus, an

" to and from the user'of it; Fig. 8 a sectional View taken on the line VIII-'VIII, Fig. 7,

and Fig. 9 a sectional view taken on the line TEL-IX, Fig. 8.

llhroughout. the specification and claims the gases exhaled by the user into the apparatus and those inhaled from the apparatus will be designated as air, although neither is Strictly atmospheric air. As is usual in apparatus of the character contemplated herein, the present apparatus includes an air circulatory system comprising a regenerator for removing carbon d1 oxide and moisture from-the exhaled air, a

cooler for the air after itha passed through the regenerator, means for automatically ,supplymg regulated quantities of oxygen to the regenerated and cooled air, andvalves for controlling the ow of air in the circulatory system. 'the means for supplying 'oxygep consists of a second series of eleis to so construct and arrange the sevments including an oxygen bottle, pressure reducer and lnlet valve. The several units forming the cireulatorqy system will first be for lightness and strength may he made of duralumin, an aluminum base alloyhaving high physical properties. Within the frame, which is of relatively small width, there is mounted a regenerator 2, and a cooler 3 which are connected, respectively, to, the lower ends of the flexible tubes 4 and 5, the upper ends of which are attached to an outlot and inletot a casing (l of a mouthpiece.

The regeneiator preferably consists of a rectangular metal casing provided interiorly with a body of granular material 7 for removing carbon dioxide and moisture from the exhaled air. The air purifying composition is arranged between screensv 8 and 9 placed near the upper and lower ends of the casing, and may he put in and removed from the casing through a suitable side filling opening 1t). At the, upper end of the regenerator there is an air inlet ll havingian exteriorly threaded nipple to which flexiblepipe 4 may be attached by means of a connecting member 12 rotatable with respect to the pipe. At the lower end of the regenera- It comprises a' relatively narrow metal.

regenerator outlet. For connecting the regenerator and cooler to each other, a thumb screw 15 extends through the lower wall of -cooler projection 14 and engages bridge member 1370f the regenerator. Suitable gaskets are arrangedbetweenjthe meetings faces of the regenerator outlet and cooler inlet as well as beneath the head of the thumb screw to prevent-leakage of air. The

upper end of the cooler provided with an outlet 16 adapted to be connected. to pipe 'of oxygen to air in the cooler.

. structlon of this valve and of the breathing bag and their manner of operation will be explained, in connection with the description of the oxygen-supplyin system."

Having reference nbw to t e mouthpiece. element of the circulatory system, the casing 6 thereof is provided centrally with a laterally-extending oblong tube 20, whichin the operation of the apparatus is-held in the mouth of the user. Casing 6 is, by offset partitions 21 and 22, divided into three compartments, a compartment 23 which is constantly in communication with tube 20, a

compartment 24.- which through pipe 4 is in communication with the regenerator, and a compartment 25 which through pipe 5 is in communication with the cooler. In the horizontal portion of partition 21 there is arranged a check valve which permits flow only from chamber 23 to chamber 24. The valve preferably consists ofa plate 26 constructed' of mica or other suitable light material adapted to rest upon the upper edge of a valve seat .27,and held in operative position by means of a cage consisting of cross strips 28 having their ends bent down- -wardly and attached to the horizontal por-' tion of partition 21. A similar valve 29 held in position by a cage 30 is arranged to control flow through an opening 31 in the horizontal offset portion of partition 22, the arrangement of valve 29 bein such that there may be flow only from chamber 25 into chamber 23. By arrangin these inlet and outlet valves in horizontal positions and constructing them in the manner explained, the liability of the valves becoming permanently unseated and of accordingly failing to function is reduced to a minimum, if not entirely eliminated.

Connected to the lower portion of the mouthpiece there is a combined saliva trap and pressure relieving valve. The saliva trap consists of a U-shaped tube 32 attached at one end to casing 6 and communicating with chamber 23 of the mouthpiece. The other end of tube 32 is adapted to be closed by a horizontally disposed valve 33 which may be, and preferably is of the same construction as the valves in mouthpiece partitions 21 and 22. The saliva trap is enclosed within a casing 34 provided with 'a horizontal partition 35 having a central opening 36. At the lower'end of casing 34 there is a closure 37 provided near its center with openings 38. On the inside of closure 37 there is a valve seat 39 for a disc valve 40 which is yieldingly pressed towards closed position by a spring 41,- but which Inaybiii opened by a stem i2 extending through closure 37. The mouthpiece is further PIE-0 vided with suitable straps 143, preferably arranged to attach it to a special cap (not shown) for the user of the apparatus to wear this being a convenient way of quickly attaching the mouthpiece to the users head and of assuring its being firmly and continuously held in proper position.

i The operation of the air circulatory system will be explained before describing the oxygen admitting system. Air exhaled by a user passes through tube 20 into compartment 23 of the mouthpiece, and the pressure of the air lifts valve 26 and permits the air to freely flow into chamber 24, and

from such chamber into and through tube 4. The pressure of the exhaled air acts upon the top of mouthpiece valve 29, already closed by gravity, and prevents such air from flowing into tube 5. The exhaled air flows from,tube 4 downwardly through the air purifying composition? in regenerator 2, by which composition carbon dioxide and moisture is removed, from the air. The purified air flows from the bottom of the regenerator into the bottom of cooler il in which oxygen is supplied 'to the air in the manner and by the apparatus presently to be explained. When the user inhales, air is drawn through pipe 5 from the cooler and from the breathing bag attached to it; Due to the pressure of-this air, which pressure is regulated by the ioxygen supplysystem, and due also to the "rarefaction effected by the inhaling operation, valve 29 of the mouthpiece rises .to permit air to flow into chamber 23 and from it through tube 20 to the user. The saliva which is almost always emitted by the user of breathing apparatusis trapped in the lower portion of chamber 23 and flows into tube If the tube fills up with saliva, valve 33 will rise and permit the saliva to flow into casing 34: from which it may be intermittently removed by pressing upwardly on valve stem 42. In case the pressure of the air in the apparatus becomes too high, it maybe lowered by opening valve 40, but no external air may be drawn into the apparatus through the saliva trap, this being pregi ented by check valve 33 at the upper endor outlet of tube 32.

Having reference now to the oxygen supplying system, oxygen under a pressure of 1 approximately 150 atmospheresis contained in a bottle 43 supported by the lower portion of frame 1. The oxygen flows to the cooler successively through a main valve, a high pressure fitting, a reducing valve, 11 125 safety valve and a control valve, and manually controlled means are provided for permittin the flow of oxygen directly from the bottle to the cooler so that in case any of the units in the oxygen supply systemshould fail to.pro erly function, oxygen may still be supp led to the air.

The construction of the main valve is shownparticularly in Figs. 3, 4 and .5. It

comprises a casing 44 having-a threaded stem 45 adapted to engage the neck of bot-' tle 43, the stem being provided centrally with a bore 46 having a contracted portion 47 near the center of the casing. Beyond this contracted portion the casing is provided with a bore 48 which receives a stem '49 of a needle valve for controlling flow through bore 47 into bore 48. Valve stem 49 is providedwith a shoulder 50 arranged in a cap packing-nut 51 so that the valve stem may not accidentally be entirely removed from the valve with consequent liability of entire loss of the oxygen in the bottle. The valve casing is provided with a side opening 52 (Fig. 3) which communicates with bore 48, andthrough which oxygen flows to the pressure reducing valve latter of which communicates with a pipe,

and other automatic control mechanism.

A special by-pass is provided between the main valve and cooler 3 so that in case any of the automatic control units fails to properly function oxygen may nevertheless be supplied to the user of the apparatus For this purpose valve casing 44 is provid'ed with bores 53 and ,54, the former of which communicates with bore 46. and the 55, connected at one end to the casing b a 'union coupling 56, and suitably attachec at its other end to the cooler. For controlling flow through bores 53 and 54, valve casing 44 is provided with a second valve 57, the end of which seats against the outer end of bore 53. Thus when it is desirable to supply oxygen directly to the cooler, valve 57 may be opened for a short intervalof time, usually not more than a second or two. A

further feature of the main valve is a safetyv cap for relieving the pressure within the oxygen bottle when, for example,- the bottle is heated above a predetermined temperature, 'a temperature at. which the pressure of the oxygen may cause the bottle to burst. The safety cap, which may be of standard construction, is indicated at 5 8 as closing the outer end of a bore 59 which communicates at its inner end with 7 here 46.

Bore 52 of the valve Teasing extends through an exteriorly threaded projection 60 of the valve casing, towhich projection ahi h pressure fitting 61 is attachedby a suit: le union coupling. This fitting is pro- 'vidd with a bore 62, the right end of which,

asviewed in Fig. 3, may be closed by a valve This valve controls flow throu h a pipe 64 connected at its lower end to tting-61, and at its upper end to a pressure gage 65, so that the user of the apparatus may, by opening the valve, observe the pressure of the valve seated until a predetermined presthe oxygen in the bottle, and thereby determine. how nearly at an end the supply of oxygen may be.

'Arranged immediately above high pressure fitting 61 is a reducing valve whereby the pressure of oxygen is reduced to about three pounds. The pressure reducer includes a valve member 66, held yieldingly upwardly by a spring 67 arranged between it and a stem 68, which stem is provided with-a central bore registering with the outer end of the bore 62 in fitting 61. The" upper end ofvalve 66 presses against one arm of a bell-crank lever 69 having a fixed pivot at 70,'and having its other arm pivoted to the innr end of a rod 71, the outer end of which rod is adjustably attached to a plate 72. Between-a casing 73 and plate 7 2 there is an expansible metal bellows diaphragm 74 formed to normally urge plate 72 inwardly so that hell-crank lever 69 normally permits valve 66 to remain in open position.

When the pressure of oxygen within casing 72 and diaphragm 74 exceeds a predetermined amount, say about three pounds, the

diaphragm suflieiently expands, against its own resiliency and the pressure of spring 67, to close valve 66. By this simple ar-- rangement the pressure of oxygen beyond valve 66 is automatically maintained'substantially constant.

Above the reducing valve, and in the line safety valve comprises a disc.'valveelement 75 yieldingly pressed toweirds its seat by a spring 7 6 of the required strength to holl sure acts upon its inner face. At the outer end of a casing77, within which the spring pressed valve is arranged, there is a whistle 78 which responds'with a sharp noise when oxygen escapes through the safety valve.

vThesafety valve and whistle are arranged at tlie outer end of a casing 7 9 adapted to be attached to the upper end of re'lueing valve casing 73, and adapted also to be .con-

nected to a. pipe SO'arranged withincooler 3 and connected tothe controlling valve 18 in thecooler.

.The last element of the oxygen. supplying system is controlling valve 18 which is operated by breathing bag 19. The con bag is attached to one end of ac lindrieal easing'81 provided with an inwardly flanged sleeve 82 at its other end. Within cylinder 81 there is a spring 83 which. atone end 'struction of this valve is shown in detail 1:5 in Fig. 6. The outer wall of the breathing and cooler. Gas

bears against the flange of sleeve 82 and at its other end against a disc 84, which disc is attached to the outer end of a valve stem 85. The inner end of this stem is provided with a disc valve 86 adapted to control flow into the end of a tube 87 arranged within spring This tube is attached to a casing 88 which in turn is fastened to the wall of the cooler. A second spring 89 is arranged within tube'ST and bears at one end against an inwardly turned flange of the tube and at its other end against a shoulder 90 formed on the valve stem. Tube 87 and casing 81 are provided with perforations as indicated to permit flow of oxygen from casing 88 into the cooler when valve 86 is open. The oxygen thus permitted to flow into the cooler mingles with the'regenerated air which oecupies both the cooler and breathing hag, there being a large. opening 61 in the cooler and bag surrounding valve 18 for placing the two into communication with each other. The breathing bag may be conveniently attached to the cooler by ,means of screws 92 arranged within open ended tubes 93 which traverse the cooler. the screws being adapted to engage studs 94 attached to and pro ecting laterally from the inner wall of the breathing ba In the operation of the oxygen supplyipg system,- valve 49 is opened to permit oxygen to flow through valve casing bores 46, 47, 48 and 52 into bore 62 of fitting 61. The pressure of the oxygen in bore 62. which it will be understood is the same or substantially the same as that in the oxygen bottle. may be observed by opening valve 63 whereby bore 62 is, through pipe 64, placed in communication with pressure gage 65. Oxygen flows through nipple 68, past valve 66 as long as the pressure within the reducing valve is below the maximum for which the valve is set. In case the reducing valve does not close when the pressure in it is mate-- rially above the predetermined maximum,

safety valve '7 5 0 ns and permits oxygen to escape, the escaping oxygen causing whistle 7 8 to blow and thereby warn the user of the apparatus that it is not properly function ing. From the safety valve the oxygen flows through pipe to casing 88 of valve 18. When the breathing bag is deflated. as

indicated in Fig. 6, valve 86 is opened to permit oxygen to flow into the breathing bag pressure in the breathing bag, effected both y exhalation andby oxygen admitted through valve 86 when open, causes the bag to expand, its outer wall moving to the left as viewed in Fig. 6. This movement of the outer breathing bag wall carries with it cylinder 81 which causes spring 83 to be compressed. Whenthe compression exerted by spring 83 overcomes that of auxiliary spring 89, valve 86 is closed, by reason of the movement of disc 84 and stem unremain dcr the pressure of spring 83. By provid ing a controlling valve having main and auxiliary springs arranged in the manner explained, such valve will not be closed as soon as the breathing bag begins to distend, and the valve will be opened before the breathing bag has returned to the deflated position in which it is indicated in Fig. 6.

It will be observed of the breathing apparatus that its several parts are so arranged that. the apparatus as a whole is of small size. In the air circulatory system the air travels a minimum distanee,-downwardly through the regenerator and upwardly through the cooler. In the oxygen supplying system practical instrumentalities are provided for etiecting eliicient' operation of the apparatus and for meeting any extraordinary conditions that may be encountered.

According to the provisions of the patent.

statute, I have described the principle and operation of my invention, together with the construction which I now consider to represent the bcst embodiment thereof. However, I desire to have it understood that, within the scope of the appended claims, my invention may be practiced by other forms of construction than that specifically shown and described. Y

I claim:

1. In a breathing apparatus, the co1nbination of a frame, a regenerator attached to the upper portion of the frame and having an air inlet at its top and an air outlet at its bottom, a cooler arranged in said frame adjacent to the regenerator and having a laterally projecting portion extending bclow the bottom of said regencrator, said projection being provided with an air inlet registering with said regenerator outlet, a screw extending through said projection and detachably connecting said regenerator and cooler to each other, an air outlet at the top of said cooler, and automatic means for supplying oxygen to the cooler,

2. In a breathingapparatus, the combination of an air circulatory system, an oxygen bottle, means intermediate said bottle and system for automatically controlling the flow of oxygen at reduced pressure to said system,v a manually operated main valve for controlling flow from the bottle to said flow-controlling means, a direct connection between said bottle and system by-pas ing said main valve and the entire flow-controlling means, and a manually-operated valve for controlling flow through said direct connection.

3. In a breathing apparatus, the combination of an air circulatory system including a regenerator and a cooler each connected directly to a mouthpiece. an oxygen bottle, a conduit including a manually-operated main valve and automatic pressure reducing and flow controlling valves connecting said bottle with said cooler, an auxiliary conduit directly till loo

connecting said bottle with said cooler and 'byzfassing said entire first named conduit,

a manually operated auxiliary valve for controlling flow through said auxiliary conduit.

. Z. In a breathing apparatus, the combine each communicating directly with said bottle, a conduit extending from one of said valves. to said cooler and includinga reducing valve and a Valve for automatacally controllingadmission to said cooler, and a conduit extending from the other valve of said casing directly to said cooler whereby oxygen may be supplied to said cooler without flowing through the first-mentioned valve and said reducing and flow controlling 20 j valves;

GEORGE s. McGAA. 

